The invention relates to a motor vehicle wiper system having an improved slide.
The invention relates more particularly to a motor vehicle wiper system of the type in which a windshield wiper is given a sweeping movement by a drive shaft which is itself made to rotate around its axis by a motor. The wiper system has a means of varying the orientation of the axis of the drive shaft. A guiding section of the shaft is held between two internal surfaces, parallel and facing one another, of a slide.
Such a wiper system is, for example, described in FR-A-2 753 942. The wiper system described in this document therefore has a drive shaft that is mounted so as to be mobile in rotation in a support by the intermediary of a spherical bearing that provides it with three degrees of freedom in rotation. However, in order to limit the range of motion possible for this shaft, it is provided that the lower end of the shaft be held in a slide in such a way that the shaft can no longer rotate except, on the one hand, around its axis, and on the other hand, around an axis containing the center of rotation of the spherical bearing and the longitudinal axis of the slide. The wiper system furthermore has a means making it possible to vary the orientation of the drive shaft around this second axis, particularly as a function of the angular position of the shaft in revolution around its own axis.
In such a system, it is important to be able to eliminate any play between the lower end of the shaft, which forms a guiding section, and the two internal surfaces of the slide, which face one another. In effect, any possibility of impact between the shaft and the slide is thus avoided, which makes it possible to limit the operating noise of the system to a great extent.
However, the shaft cannot be held too tightly inside the slide, under penalty of increasing the friction between the shaft and the slide, which is detrimental, on the one hand, to the efficiency of the mechanism and therefore to the energy consumption necessary to ensure movement, and on the other hand, to a satisfactory working life of the mechanism because of wear and tear due to friction.
The invention therefore aims to propose a new design of a wiper system which, while making possible operation without jolts, without impact, and therefore without noise, allows better control of the tightness of the guiding section of the shaft within the slide.
For this purpose, the invention proposes a wiper system of the above type characterized by the fact that at least one of the internal surfaces of the slide is formed by a friction plate whose external surface cooperates with deformable means interposed between the friction plate and a stationary wall of the slide in order to permit a displacement of the friction plate along a transverse direction perpendicular to the plane of the plate, and by the fact that when the guiding section is held in the slide, the deformable means act on the plate in such a way that the section rests simultaneously against the two opposite internal surfaces of the slide.
According to other characteristics of the invention:
the deformable means consist of a plate made of elastomeric material whose interior surface rests against the external surface of the plate and whose exterior surface rests against the wall of the slide;
the deformable plate has raised protuberances on at least one of its surfaces;
the raised protuberances are in the form of bars;
the raised protuberances are in the form of wavy bars;
the raised protuberances are in the form of stubs;
the stubs are roughly cylindrical and solid;
the deformable plate has, on its surface opposite that which bears the protuberances, recesses made to correspond with the protuberances;
the protuberances are arranged on the interior surface of the deformable plate;
the protuberances are arranged on the exterior surface of the deformable plate;
the deformable plate is produced by extrusion;
the deformable plate is produced by molding;
the deformable plate is molded onto the friction plate;
the deformable plate is glued to the friction plate;
the deformable plate has, at its two longitudinal ends, caps which extend transversely towards the interior from the interior surface of the plate and each of which delimits a housing, the two housings being open longitudinally in the direction of one another so that each can hold a corresponding longitudinal end of the friction plate;
the slide has two opposite stationary walls, two friction plates, and two deformable elements which are interposed respectively between one of the plates and one of the walls, and the guiding section of the shaft is held tightly between the two friction plates;
the two deformable elements are produced in the form of a dampener block in a single piece; and
the dampener block is molded around the two friction plates.